diff --git a/usr.bin/lex/flex.skl b/usr.bin/lex/flex.skl
index 602095095fb2..d7416521f80f 100644
--- a/usr.bin/lex/flex.skl
+++ b/usr.bin/lex/flex.skl
@@ -456,9 +456,9 @@ YY_MALLOC_DECL
 
 YY_DECL
 	{
-	register yy_state_type yy_current_state;
-	register char *yy_cp, *yy_bp;
-	register int yy_act;
+	yy_state_type yy_current_state;
+	char *yy_cp, *yy_bp;
+	int yy_act;
 
 %% user's declarations go here
 
@@ -751,9 +751,9 @@ static int yy_get_next_buffer()
 int yyFlexLexer::yy_get_next_buffer()
 %*
 	{
-	register char *dest = yy_current_buffer->yy_ch_buf;
-	register char *source = yytext_ptr;
-	register int number_to_move, i;
+	char *dest = yy_current_buffer->yy_ch_buf;
+	char *source = yytext_ptr;
+	int number_to_move, i;
 	int ret_val;
 
 	if ( yy_c_buf_p > &yy_current_buffer->yy_ch_buf[yy_n_chars + 1] )
@@ -887,8 +887,8 @@ static yy_state_type yy_get_previous_state()
 yy_state_type yyFlexLexer::yy_get_previous_state()
 %*
 	{
-	register yy_state_type yy_current_state;
-	register char *yy_cp;
+	yy_state_type yy_current_state;
+	char *yy_cp;
 
 %% code to get the start state into yy_current_state goes here
 
@@ -918,7 +918,7 @@ yy_state_type yy_current_state;
 yy_state_type yyFlexLexer::yy_try_NUL_trans( yy_state_type yy_current_state )
 %*
 	{
-	register int yy_is_jam;
+	int yy_is_jam;
 %% code to find the next state, and perhaps do backing up, goes here
 
 	return yy_is_jam ? 0 : yy_current_state;
@@ -928,17 +928,17 @@ yy_state_type yyFlexLexer::yy_try_NUL_trans( yy_state_type yy_current_state )
 %-
 #ifndef YY_NO_UNPUT
 #ifdef YY_USE_PROTOS
-static void yyunput( int c, register char *yy_bp )
+static void yyunput( int c, char *yy_bp )
 #else
 static void yyunput( c, yy_bp )
 int c;
-register char *yy_bp;
+char *yy_bp;
 #endif
 %+
-void yyFlexLexer::yyunput( int c, register char* yy_bp )
+void yyFlexLexer::yyunput( int c, char* yy_bp )
 %*
 	{
-	register char *yy_cp = yy_c_buf_p;
+	char *yy_cp = yy_c_buf_p;
 
 	/* undo effects of setting up yytext */
 	*yy_cp = yy_hold_char;
@@ -946,10 +946,10 @@ void yyFlexLexer::yyunput( int c, register char* yy_bp )
 	if ( yy_cp < yy_current_buffer->yy_ch_buf + 2 )
 		{ /* need to shift things up to make room */
 		/* +2 for EOB chars. */
-		register int number_to_move = yy_n_chars + 2;
-		register char *dest = &yy_current_buffer->yy_ch_buf[
+		int number_to_move = yy_n_chars + 2;
+		char *dest = &yy_current_buffer->yy_ch_buf[
 					yy_current_buffer->yy_buf_size + 2];
-		register char *source =
+		char *source =
 				&yy_current_buffer->yy_ch_buf[number_to_move];
 
 		while ( source > yy_current_buffer->yy_ch_buf )
@@ -1479,7 +1479,7 @@ yyconst char *s2;
 int n;
 #endif
 	{
-	register int i;
+	int i;
 	for ( i = 0; i < n; ++i )
 		s1[i] = s2[i];
 	}
@@ -1493,7 +1493,7 @@ static int yy_flex_strlen( s )
 yyconst char *s;
 #endif
 	{
-	register int n;
+	int n;
 	for ( n = 0; s[n]; ++n )
 		;
 
diff --git a/usr.bin/lex/flexdef.h b/usr.bin/lex/flexdef.h
index 03651ea965b8..ddc876876093 100644
--- a/usr.bin/lex/flexdef.h
+++ b/usr.bin/lex/flexdef.h
@@ -814,10 +814,10 @@ extern void action_define PROTO(( char *defname, int value ));
 extern void add_action PROTO(( char *new_text ));
 
 /* True if a string is all lower case. */
-extern int all_lower PROTO((register char *));
+extern int all_lower PROTO((char *));
 
 /* True if a string is all upper case. */
-extern int all_upper PROTO((register char *));
+extern int all_upper PROTO((char *));
 
 /* Bubble sort an integer array. */
 extern void bubble PROTO((int [], int));
@@ -829,10 +829,10 @@ extern void check_char PROTO((int c));
 extern Char clower PROTO((int));
 
 /* Returns a dynamically allocated copy of a string. */
-extern char *copy_string PROTO((register const char *));
+extern char *copy_string PROTO((const char *));
 
 /* Returns a dynamically allocated copy of a (potentially) unsigned string. */
-extern Char *copy_unsigned_string PROTO((register Char *));
+extern Char *copy_unsigned_string PROTO((Char *));
 
 /* Shell sort a character array. */
 extern void cshell PROTO((Char [], int, int));
@@ -934,7 +934,7 @@ extern int link_machines PROTO((int, int));
 /* Mark each "beginning" state in a machine as being a "normal" (i.e.,
  * not trailing context associated) state.
  */
-extern void mark_beginning_as_normal PROTO((register int));
+extern void mark_beginning_as_normal PROTO((int));
 
 /* Make a machine that branches to two machines. */
 extern int mkbranch PROTO((int, int));
@@ -997,7 +997,7 @@ extern int yywrap PROTO((void));
 /* from file sym.c */
 
 /* Add symbol and definitions to symbol table. */
-extern int addsym PROTO((register char[], char*, int, hash_table, int));
+extern int addsym PROTO((char[], char*, int, hash_table, int));
 
 /* Save the text of a character class. */
 extern void cclinstal PROTO ((Char [], int));
@@ -1006,7 +1006,7 @@ extern void cclinstal PROTO ((Char [], int));
 extern int ccllookup PROTO((Char []));
 
 /* Find symbol in symbol table. */
-extern struct hash_entry *findsym PROTO((register char[], hash_table, int ));
+extern struct hash_entry *findsym PROTO((char[], hash_table, int ));
 
 extern void ndinstal PROTO((char[], Char[]));	/* install a name definition */
 extern Char *ndlookup PROTO((char[]));	/* lookup a name definition */
diff --git a/usr.bin/lex/lex.1 b/usr.bin/lex/lex.1
index b41de37986a2..38eecf1126da 100644
--- a/usr.bin/lex/lex.1
+++ b/usr.bin/lex/lex.1
@@ -945,7 +945,7 @@ the following is one way to eat up C comments:
 
     %%
     "/*"        {
-                register int c;
+                int c;
 
                 for ( ; ; )
                     {
diff --git a/usr.bin/lex/parse.y b/usr.bin/lex/parse.y
index dc71379b3ee2..f3b56d82febc 100644
--- a/usr.bin/lex/parse.y
+++ b/usr.bin/lex/parse.y
@@ -782,7 +782,7 @@ string		:  string CHAR
 
 void build_eof_action()
 	{
-	register int i;
+	int i;
 	char action_text[MAXLINE];
 
 	for ( i = 1; i <= scon_stk_ptr; ++i )
diff --git a/usr.bin/lex/scan.l b/usr.bin/lex/scan.l
index cee8a16d2def..b109a50a358e 100644
--- a/usr.bin/lex/scan.l
+++ b/usr.bin/lex/scan.l
@@ -434,7 +434,7 @@ LEXOPT		[aceknopr]
 			}
 
 	"{"{NAME}"}"	{
-			register Char *nmdefptr;
+			Char *nmdefptr;
 			Char *ndlookup();
 
 			strcpy( nmstr, yytext + 1 );